Refrigerated display case



NOV. 6 A KNAPP REFRIGERATED DISPLAY CASE Filed Sept. 18, 1950 2Sheets-Sheet 2 .nm hm WM I INVENTOR.

My 8- BY 3 Patented Nov. (i, 1934 REFRIGERATED DISPLAY CASE Andrew E.Knapp. De

troit, Mich, assignor to Kelvinator Corporation, Detroit, Mich, acorporation of Michigan Application September 18, 1930, Serial No.482,732

Claims.

This invention relates to refrigerating apparatus and more particularlyto refrigerated display cases.

Heretofore, the primary function of refrigerated display cases has beento preserve foods and other supplies adversely affected by atmospherictemperature, at a suitable low temperature normally considerably above afreezing temperature. Recently a new art of preserving and merchandisingfood has become popular. This art is based upon freezing certain foodsand keeping them in that condition until delivered to the ultimateconsumer. A need has therefore arisen for display cases adapted topreserve such supplies in a frozen condition. At the same time, therestill exists a need for refrigerated display cases to store and displayfoods which should be kept at a normally refrigerated temperature, thatis, a temperature somewhat above freezing.

The principal object of this invention is to provide a refrigerateddisplay case adapted to store and display not only normally refrigeratedfoods but also frozen supplies.

Another object of the invention is the provision of a refrigerateddisplay case adapted to be manufactured in two parts, which parts can bereadily assembled or disassembled.

Still a further object of the invention is to provide a refrigerateddisplay case designed to be maintained at below freezing temperaturewhich will not permit a rapid lossof the cold air from the inside whensupplies are being placed thereinor taken therefrom.

Another object of the invention is the provision of a plurality ofvertically spaced storage shelves in a refrigerated display case, eachof which is ac- .cessible from an opening above-the shelves.

Other objects of the invention, more or less ancillary or incidental tothe foregoing, will appear from the following description in connectionwith the accompanying drawings. e

For a better understanding of the invention ref erence may now be had tothe attached drawings,

front wall 12, rear wall '7, and a partial top wall 13. The bottom walland side walls are provided with an inner lining 5 and an outer casing6. Suitable insulation material 4 is disposed between the inner liningand the outer casing. The upper surface of the bottom wall 8 inclinesdownwardly from the front wall to the rear wall and is provided adjacentthe rear wall with an opening through which a drain pipe 3 extends. Thetop section 11 is provided with suitable insulated end walls 25, arearwardly extending front wall 23, a top wall 22, and a forwardlyextending rear wall 24. The front wall 23 is provided with a windowsection 26 consisting of a plurality of spaced plates of glass 27 sealedabout their edges in a frame 28. The inner surface of the top wall 22and the upper portion of the inner surface of the rear wall 24 areprovided with suitable insulation 4.

The upper extremity of the front wall 12, the lateral frame member 14carried on the forward edge of the partial top wall 13, and the upperextremities of the side walls 9 of the base are of suitable constructionto securely engage the lower extremities of the corresponding walls ofthe top section 11. The lower extremity of the front wall 23 of the topsection 11 is provided with a lateral groove 21 adapted to receive theupper extremity of the front wall 12 of the base 10. Suitable securingmeans, not shown, which may be of any standard construction, are used toremovably secure the lower extremities of the walls of the top sectionto the upper extremities of the walls of the base.

The provision for removably attaching the top section to the base notonly greatly facilitates the transportation of applicants display casebut also effects a considerable saving in the construction thereof.Other advantages, such as accessibility for repairs, are also incidentalto this type of construction.

Access to the interior of the upper portion of. the display case isprovided by means of doors 29, positioned in the rear wall 24 of the topsection 11. The doors consist of a plurality of plates of glass 41sealed about their edges in a door frame 42. Hinges operatively connectthe doors 29 to the lower portion of the rear wall 24 and permit theopening of the doors rearwardly and downwardly. The upper edges of thedoors and the rear wall 24 adjacent thereto are provided with suitablelatch equipment 31 for securing the doors in closed position. Access tothe interior of the lower part of the display case is provided by meansof Openings 17 in the partial top wall 13. Suitably insulated doors 15,secured to the top wall 13 by means of hinges 19, are adapted to closethe openings 1'7. Handles 18, by which the doors 15 may be raised andswung back upon their hinges, are carried on the upper surface of thedoors on the edges thereof remote from the hinges.

One of the most common causes for inefficient operation of refrigerateddisplay cases is the loss of cold air from the inside of the case whenthe doors are opened for the insertion or withdrawal of supplies kepttherein. I have utilized the well known fact that cold air is heavierthan warm air, in overcoming this loss. This has been accomplished by sopositioning the doors that the air inside the case would have to rise inorder to escape through the door openings. The doors 29 are hinged attheir lower edges, so that when partially opened for normal use theywill act as a baffle or obstruction to keep the air from tumbling out ofthe case. The doors 15 are located in a horizontal wall so that theheavier air inside the case has no opportunity to escape through theopenings made when they are swung back upon their hinges. This provisionfor keeping the cold air within the case also keeps the warm air outthereby preventing clouding of the'windows of the case resulting fromcondensation when warm air strikes their cold surface.

The base 10 is provided at intervals throughout its length with a set ofthree vertically spaced angle irons or rails 37 extending from the frontwall to the rear wall thereof. The angle irons 37 are adapted tosupport, on their upper surface,

shelves 38 equipped with rollers 39. The shelves 38 are of suchproportions that when their forward edges are against the inner side ofthe front wall 12 their rear edges are remote from the rear wall '7.Access may be had to each of the shelves through the opening 1'7 bysliding the shelves along the angle irons 3'7 toward the rear wall 7.This arrangement permits the convenient utilization of a greater amountof storage space within the display case than would be possible in acase of similar construction if fixed shelves were used. The upperportion or the top section of the display case is equipped with a shelf34 secured to the rear wall 24 below the doors 29. The shelf 34,disposed in the upper portion of the display case, and the top series ofslidable shelves 38, disposed in the'base 10, expose their contents tothe view of prospective purchasers through the window 26. The suppliesdisplayed on the top series of shelves 38 may be replenished whennecessary from supplies stored on the lower shelves without exposing thesupplies to the warmer outside air.

Refrigerant evaporators 32, 35 and 40 are disposed in the uppermostextremity of the display case, beneath the shelf 34 adjacent the rearwall of the top section 11, and beneath the topmost angle iron 37,respectively. Bafile plates 33 are positioned at the lower sides andbeneath the evaporator 32 to direct the circulation of air about theevaporator. The lower extremity of one of the baffle plates 33 is foldedback upon itself to form a trough 2 communicating with a waste disposalpipe for carrying off the moisture resulting from the defrosting of theevaporator 32. Similarly a bafiie plate 36 is positioned below theevaporator 35 to influence the direction of the air circulating-aboutthat evaporator. The

evaporator 40 may be secured to the lower surface of the uppermost angleiron 37. Eachof the evaporators 32, 35 and 40 extend throughout theentire length of the display case. Three separate evaporators are showndisposed in the display case presented in the drawings made a part ofthis specification, but it should be understood that the purposes ofthis invention could be equally well served by eliminating theevaporator 35 or by the installation of additional evaporators. All ofthe evaporators are operatively connected to a refrigerantcompressorcondenser structure, not shown, by means of suitablerefrigerant conduits comprising a suction line and a liquid line.

Although the evaporators herein described are designed to be operatedfrom a single compressorcondenser structure, it is to be understood thatthey may also be operated by separate compressor-condenser structures.

Suitable well known valve structures are associated with the refrigerantlines connecting the evaporators to the compressor-condenser apparatus,for causing the refrigerant to evaporate at different temperatures inthe respective evaporators mentioned above.

The evaporator 32 disposed in the upper portion of the case is designedto operate between wide temperature limits that are relatively high, andto maintain the air adjacent thereto at a temperature somewhat above thefreezing point. The evaporators 35 and 40 are designed to operatebetween narrow temperature limits and to maintain the air adjacentthereto at a temperature considerably below the freezing point. The basesection 10 of the case is adapted to be used for the storage and displayof the new frozen foods while supplies required to be kept at normallyrefrigerated temperatures may be displayed on the shelf 34 in the topsection 11.

It is essential to the satisfactory preservation of the frozen foodsthat they be kept in a frozen state until ready for use. A refrigerateddisplay case suitable for the preservation of such foods must thereforebe kept constantly at a temperature below the freezing point.Considerable difficulty has been experienced heretofore in keepingdisplay cases at a constant low temperature because the evaporators usedin such cases acquire a deposit of frost on their surfaces as a resultof the condensation of moisture from the air. As this frost accumulatesthrough the addition of warm air from time to time, it impairs theefficiency of the evaporator to such an extent that ultimately itbecomes necessary to interrupt the operation of the refrigeratingapparatus to permit the frost to melt. While the evaporators are beingdefrosted, the temperature within the case of course rises to arelatively high value.

Applicant has arranged the evaporators in his display casein such amanner that it is not necessary to defrost those in the low temperaturecompartment. This is made possible by the fact that the air confined inthe display case at a given time does not contain enough moisture whendeposited on the evaporators in the form of frost to materially effecttheir efficiency. Applicants case is so constructed that once a lowtemperature is obtained in the base section and the moisture containedin that section is deposited on the evaporators 35 and 40, no furthersubstantial amount of warm air or moisture laden air is admitted theretoso long as the refrigerating apparatus continues to operate even thoughthe doors 15 are frequently opened. Any warm air or moisture laden airthat does get into the box through leakage or through the doors willrise to the top of the case and give up its moisture to the evaporator32 in the form of frost deposited on the surface thereof. Inasmuch asthis evaporator operates between temperature limits that are relativelyhigh, it will be defrosted on each off cycle and the moisture resultingtherefrom will be carried away by the trough 2 formed at the lowerextremity of the baffle 33.

It will be apparent from the foregoing description that the evaporator40 will keep the air confined beneath it at a relatively lowtemperature, and that that air will circulate beneath the evaporator butwill not have an opportunity to rise above it. The refrigeratingsurfaces of the evaporator 40, including the tubes and fins, arejuxtaposed and cooperate with the shelf thereabove to form in effect awall or barrier for resisting convection of air currents between thecompartments or sections of the case. Likewise, the evaporator 35 willcause the air adjacent thereto to circulate beneath it and permit butlittle to pass above it, while the evaporator 32 will supply thenecessary temperature difference for the circulation of warmer air inthe top section 11. The evaporator 32 will also collect on its surfacein the form of frost, the excess moisture for the entire case, therebyeliminating the necessity for frequently defrosting the evaporators 35and 40.

It will be apparent to those skilled in the art that the structuredisclosed herein is merely illustrative of the invention and that manymodifications and changes may be made in such structure withoutdeparting from the spirit of the invention or from the scope of theappended claims.

I claim:

1. In a refrigerated display case having an opening in the top wallthereof, a plurality of vertically spaced shelves slidably positioned insaid case beneath said opening, horizontally positioned heat absorbingmeans disposed directly below one of said shelves and above another ofsaid shelves, and closure means for said opening.

2. A refrigerated display case comprising an insulated base, a topsection provided with a transparent wall, a plurality of verticallyspaced shelves disposed in said base section and. being arranged to bemoved laterally to expose the upper surface of a lower shelf, andhorizontally positioned heat absorbing means disposed between two ofsaid shelves.

3. A refrigerated display and storage case having storage and displaycompartments arranged one above the other and in open communication witheach other, a refrigerant evaporator disposed in the upper compartmentfor cooling articles stored in said compartment at temperatures abovethe freezing point of water, a refrigerant evaporator disposedimmediately below the opening between said compartment for coolingarticles stored therebelow at temperatures below the freezing point ofwater, a shelf disposed in said lower compartment for supportingarticles immediately above said latter evaporator, said uppercompartment being provided with a transparent wall so that the contentsof the upper compartment and the articles stored on said shelf arevisible through said opening, and a refrigerant evaporator disposeddirectly over at least a portion of said shelf for cooling the airtherebelow at temperatures below the freezing point of water, saidsecond named evaporator preventing any of the air thereabove frompassing into contact with articles stored therebelow before firstcontacting with said evaporator.

4. A refrigerated case having food. storage compartments arrangedadjacent and in open communication with each other, means for coolingsaid compartments to difierent temperatures including an evaporatordisposed in one of said compartments, and means including a secondevaporator having juxtaposed refrigerating surfaces disposed immediatelyadjacent the opening between said compartments, said last means forminga barrier for resisting convection of air between said compartments.

5. A refrigerated case having food storage compartments arranged oneabove the other and in open communication with each other, means for 115cooling said compartments to different temperatures including anevaporator disposed in the upper compartment, and means including asecond evaporator having juxtaposed refrigerating surfaces disposedimmediately adjacent the open- 120 ing between said compartments, saidlast means forming a barrier for resisting convection of air betweensaid compartments.

ANDREW E. KNAPP.

